1 /* $NetBSD: subr_humanize.c,v 1.1 2009/10/02 15:48:41 pooka Exp $ */ 2 3 /*- 4 * Copyright (c) 1997, 1998, 1999, 2002, 2007, 2008 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Luke Mewburn. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include <sys/cdefs.h> 33 __KERNEL_RCSID(0, "$NetBSD: subr_humanize.c,v 1.1 2009/10/02 15:48:41 pooka Exp $"); 34 35 #include <sys/types.h> 36 #include <sys/systm.h> 37 38 /* 39 * snprintf() `bytes' into `buf', reformatting it so that the number, 40 * plus a possible `x' + suffix extension) fits into len bytes (including 41 * the terminating NUL). 42 * Returns the number of bytes stored in buf, or -1 if there was a problem. 43 * E.g, given a len of 9 and a suffix of `B': 44 * bytes result 45 * ----- ------ 46 * 99999 `99999 B' 47 * 100000 `97 kB' 48 * 66715648 `65152 kB' 49 * 252215296 `240 MB' 50 */ 51 int 52 humanize_number(char *buf, size_t len, uint64_t bytes, const char *suffix, 53 int divisor) 54 { 55 /* prefixes are: (none), kilo, Mega, Giga, Tera, Peta, Exa */ 56 const char *prefixes; 57 int r; 58 uint64_t umax; 59 size_t i, suffixlen; 60 61 if (buf == NULL || suffix == NULL) 62 return (-1); 63 if (len > 0) 64 buf[0] = '\0'; 65 suffixlen = strlen(suffix); 66 /* check if enough room for `x y' + suffix + `\0' */ 67 if (len < 4 + suffixlen) 68 return (-1); 69 70 if (divisor == 1024) { 71 /* 72 * binary multiplies 73 * XXX IEC 60027-2 recommends Ki, Mi, Gi... 74 */ 75 prefixes = " KMGTPE"; 76 } else 77 prefixes = " kMGTPE"; /* SI for decimal multiplies */ 78 79 umax = 1; 80 for (i = 0; i < len - suffixlen - 3; i++) { 81 umax *= 10; 82 if (umax > bytes) 83 break; 84 } 85 for (i = 0; bytes >= umax && prefixes[i + 1]; i++) 86 bytes /= divisor; 87 88 r = snprintf(buf, len, "%qu%s%c%s", (unsigned long long)bytes, 89 i == 0 ? "" : " ", prefixes[i], suffix); 90 91 return (r); 92 } 93 94 int 95 format_bytes(char *buf, size_t len, uint64_t bytes) 96 { 97 int rv; 98 size_t nlen; 99 100 rv = humanize_number(buf, len, bytes, "B", 1024); 101 if (rv != -1) { 102 /* nuke the trailing ` B' if it exists */ 103 nlen = strlen(buf) - 2; 104 if (strcmp(&buf[nlen], " B") == 0) 105 buf[nlen] = '\0'; 106 } 107 return (rv); 108 } 109